Kinematics of whip spider pedipalps: a 3D comparative morpho-functional approach     

Michel SCHMIDT  Roland R. MELZER  Russell D. C. BICKNELL 《Integrative zoology》2022,17(1):156-167

Amblypygi are tropical and subtropical ambush predators that use elongated, raptorial pedipalps for different activities. Although pedipalp use in predation and courtship has been explored in videography in vivo analyses, kinematic ex vivo examination of these appendages has not been conducted. Here, we rectify this lack of data by using micro-CT scans to 3D-kinematically model the appendage morphology and the range of motion (ROM) of the joints for Damon medius and Heterophrynus elaphus. We illustrate the successful application of this technique to terrestrial euarthropods in determining the maximum ROM values for each pedipalp joint. We also note that, in life, these values would be lower due to motion restricting structures like tendons, arthrodial membranes, and muscles. We further compare our maximum values obtained here with data from video-based motion analyses. The ROM of each joint shows the greatest flexibility in the femur-tibia joint (140–150°), the lowest in the basitarsus-claw joint (35–40°). ROM in the tibia-basitarsus joint is markedly distinct (D. medius: 44°; H. elaphus: 105°). This disparity reflects how H. elaphus uses the joint in the capture basket, while D. medius uses the femur-tibia joint to form the capture basket. We further illustrate notable vertical motion of the H. elaphus pedipalp compared to D. medius. This difference reflects the retro-ventral trochanter apophysis of H. elaphus. Our study opens the possibility to further whip spider kinematic understanding. Examination of other taxa using this approach will result in a more comprehensive understanding of the ecological significance and ethological implications of this unique arachnid group.  相似文献   

Trees of prosperity: Agroforestry,markets and the African smallholder     

Russell  D.  Franzel  S. 《Agroforestry Systems》2004,61(1-3):345-355

Agroforestry Systems - In many developing countries, especially in Africa, farmers have been introduced to agroforestry with little consideration for the markets for trees and tree products aside...  相似文献   

Kinetics of leaf temperature fluctuation affect isoprene emission from red oak (Quercus rubra) leaves     

Singsaas EL  Laporte MM  Shi JZ  Monson RK  Bowling DR  Johnson K  Lerdau M  Jasentuliytana A  Sharkey TD 《Tree physiology》1999,19(14):917-924

Because the rate of isoprene (2-methyl-1,3-butadiene) emission from plants is highly temperature-dependent, we investigated natural fluctuations in leaf temperature and effects of rapid temperature change on isoprene emission of red oak (Quercus rubra L.) leaves at the top of the canopy at Harvard Forest. Throughout the day, leaves often reached temperatures as much as 15 degrees C above air temperature. The highest temperatures were reached for only a few seconds at a time. We compared isoprene emission rates measured when leaf temperature was changed rapidly with those measured when temperature was changed slowly. In all cases, isoprene emission rate increased with increasing leaf temperature up to about 32 degrees C and then decreased with higher temperatures. The temperature at which isoprene emission rates began to decrease depended on how quickly measurements were made. Isoprene emission rates peaked at 32.5 degrees C when measured hourly, whereas rates peaked at 39 degrees C when measurements were made every four minutes. This behavior reflected the rapid increase in isoprene emission rate that occurred immediately after an increase in leaf temperature, and the subsequent decrease in isoprene emission rate when leaf temperature was held steady for longer than 20 minutes. We concluded that the observed temperature response of isoprene emission rate is a function of measurement protocol. Omitting this parameter from isoprene emission models will not affect simulated isoprene emission rates at mild temperatures, but can increase isoprene emission rates at high temperatures.  相似文献   

Effect of site preparation on survival and growth of Douglas-fir (Pseudotsuga menziessi Mirb. Franco.) seedlings     

Russell T. Graham  Alan E. Harvey  Martin F. Jurgensen 《New Forests》1989,3(1):89-98

The performance (survival and growth) of Douglas-fir (Pseudotsuga menziesii Mirb. Franco.) seedlings planted in minimally disturbed, scalped, and bedded soils, both with and without herbicidal control of weeds, were compared. Douglas-fir growing for 3 years in bedded soils treated with herbicide were heavier, taller, and had deeper root systems than trees growing in other preparations. Scalping did not improve seedling performance when compared to minimally disturbed soils. Soils rich in organic matter benefited tree growth. Competing vegetation in raised beds was detrimental to seedling performance.  相似文献   

Water movement in yellow-cedar seedlings and rooted cuttings: comparison of whole plant and root system pressurization methods     

Grossnickle SC  Russell JH 《Tree physiology》1990,6(1):57-68

One-year-old yellow-cedar (Chamaecyparis nootkatensis (D. Don) Spach) seedlings and rooted cuttings were taken from cold-storage facilities and grown in aerated water in a controlled environment room for 21 days. Root areas of seedlings and rooted cuttings were initially comparable, but after 21 days seedlings had produced more than twice as much new root area as rooted cuttings. Water flow resistance through the plant-atmosphere continuum decreased in both stock types over the 21-day period. In both seedlings and rooted cuttings, transpirational flux density increased in a curvilinear manner as new root area increased. Root resistance to water movement decreased sharply with increasing new root area up to 20 cm(2) in both seedlings and rooted cuttings. Further increases in new root area did not result in further changes in root resistance of either stocktype. Plant water movement was measured by both the whole plant and the root system pressurization methods with results differing between the two techniques.  相似文献   

Plexogenic pulmonary arteriopathy in a cat with non‐restrictive ventricular septal defect and chronic pulmonary hypertension          下载免费PDF全文

D. S. Russell  B. A. Scansen  L. Himmel 《The Journal of small animal practice》2015,56(8):524-529

A 10‐week‐old, male, domestic long‐hair cat was medically managed for congenital heart disease over a period of 8 years. Regular clinical examinations, including sequential echocardiography, documented a non‐restrictive paramembranous ventricular septal defect, secundum‐type atrial septal defect and aortic dextroposition. Pulmonary arterial hypertension was diagnosed by the presence of high‐velocity tricuspid regurgitation, bidirectional low velocity flow across the ventricular septal defect, pulmonary arterial dilation and severe right ventricular hypertrophy without evidence of pulmonary outflow tract obstruction. The cat remained clinically stable until it died suddenly at 8 years of age. Histopathology of the lungs found evidence of plexogenic pulmonary arteriopathy. Despite severe pulmonary vascular lesions, other post‐mortem evidence of right heart failure was lacking and death was attributed to a fatal cardiac arrhythmia. In this case report of a cat with chronic pulmonary hypertension over 8 years, plexogenic lesions were found on histopathology. The microscopic findings resemble those previously reported in dogs.  相似文献   

The Control of Reactive Oxygen Species Influences Porcine Oocyte In Vitro Maturation          下载免费PDF全文

GM Alvarez  SA Morado  MP Soto  GC Dalvit  PD Cetica 《Reproduction in domestic animals》2015,50(2):200-205

The aim of this study was to examine the effect of varying intracellular reactive oxygen species (ROS) levels during oocyte in vitro maturation with enzymatic ROS production systems (xanthine + xanthine oxidase or xanthine + xanthine oxidase + catalase), scavenger systems (catalase or superoxide dismutase + catalase) or cysteine on porcine oocyte maturation. Oocyte ROS levels showed an increase when H₂O₂ or O₂?^‐ production systems were added to the culture medium (p < 0.05). On the other hand, the presence of ROS scavengers in the maturation medium did not modify oocyte ROS levels compared with the control after 48 h of maturation, but the addition of cysteine induced a decrease in oocyte ROS levels (p < 0.05). The ROS production systems used in this work did not modified the percentage of oocyte nuclear maturation, but increased the decondensation of sperm head (p < 0.05) and decreased the pronuclear formation (p < 0.05). In turn, the addition of O₂?^‐ and H₂O₂ scavenging systems during in vitro maturation did not modify the percentage of oocytes reaching metaphase II nor the oocytes with decondensed sperm head or pronuclei after fertilization. However, both parameters increased in the presence of cysteine (p < 0.05). The exogenous generation of O₂?^‐ and H₂O₂ during oocyte in vitro maturation would not affect nuclear maturation or later sperm penetration, but most of the spermatozoa cannot progress to form the pronuclei after fusion with the oocyte. The decrease in endogenous ROS levels by the addition of cysteine would improve pronuclear formation after sperm penetration.  相似文献   

Telomere Length and Telomerase Activity in Bovine Pre‐implantation Embryos In Vitro          下载免费PDF全文

GC Gilchrist  P Kurjanowicz  FV Mereilles  WA King  J LaMarre 《Reproduction in domestic animals》2015,50(1):58-67

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Psychosocial and demographic predictors of fruit, juice and vegetable consumption among 11-14-year-old Boy Scouts     

Gallaway MS  Jago R  Baranowski T  Baranowski JC  Diamond PM 《Public health nutrition》2007,10(12):1508-1514

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Coil Embolization of a Palatine Artery Pseudoaneurysm in a Gelding     

Nathaniel R. McClellan DVM  Margaret C. Mudge VMD  Diplomate ACVS  ACVECC  Brian A. Scansen DVM  MS  Diplomate ACVIM  Stephen S. Jung MD  FACR  Duncan Russell BVMS  Diplomate ACVP 《Veterinary surgery : VS》2014,43(4):487-494

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